I have some strange noisy places in render
I can see this grainy fields also on the left side of the picture, only maybe not that obvious. Are you using Cycles? => more samples should help.

Could also happen in the image compression for example if you save as .jpeg => try an uncompressed image format

EDIT: 200 samples are still not very much. You get clean image at this size from about 500 samples. Especially for renderings with very small or weak lightning, transparencies and reflections Cycles gets very noisy.

Anywhay you should read this article where further omptimzing possibilities are explained